3,107 research outputs found
Decision-making for unmanned aerial vehicle operation in icing conditions
With the increased use of unmanned aerial systems
(UAS) for civil and commercial applications, there is
a strong demand for new regulations and technology that
will eventually permit for the integration of UAS in
unsegregated airspace. This requires new technology to
ensure sufficient safety and a smooth integration process.
The absence of a pilot on board a vehicle introduces new
problems that do not arise in manned flight. One challenging
and safety-critical issue is flight in known icing
conditions. Whereas in manned flight, dealing with icing is
left to the pilot and his appraisal of the situation at hand; in
unmanned flight, this is no longer an option and new
solutions are required. To address this, an icing-related
decision-making system (IRDMS) is proposed. The system
quantifies in-flight icing based on changes in aircraft performance
and measurements of environmental properties,
and evaluates what the effects on the aircraft are. Based on
this, it determines whether the aircraft can proceed, and
whether and which available icing protection systems should be activated. In this way, advice on an appropriate
response is given to the operator on the ground, to ensure
safe continuation of the flight and avoid possible accidents
An Empirical Investigation of Antecedents of Internet Abuse in the Workplace
engage in Internet abuse, and whether any of 15 antecedents predict the amount of that abuse. Data were collected from 571 Usenet users in an on-line survey. Aggregating the time for each of the eleven listed methods of Internet abuse revealed a total of 5.8 hours per week, on average. Most of the antecedents in two of the three Theory of Planned Behavior (TPB) categories (Attitudes and Subjective Norms), were significant, and none of the antecedents in the third TPB category (Perceived Behavioral Control) showed significance. addiction, self-justification, job satisfaction, peer culture, and supervisor culture were significant predictors of Internet abuse. Exploratory demographic factors computer experience, gender, and firm revenue also showed predictive power
The evolution of transcription-associated biases of mutations across vertebrates
<p>Abstract</p> <p>Background</p> <p>The interplay between transcription and mutational processes can lead to particular mutation patterns in transcribed regions of the genome. Transcription introduces several biases in mutational patterns; in particular it invokes strand specific mutations. In order to understand the forces that have shaped transcripts during evolution, one has to study mutation patterns associated with transcription across animals.</p> <p>Results</p> <p>Using multiple alignments of related species we estimated the regional single-nucleotide substitution patterns along genes in four vertebrate taxa: primates, rodents, laurasiatheria and bony fishes. Our analysis is focused on intronic and intergenic regions and reveals differences in the patterns of substitution asymmetries between mammals and fishes. In mammals, the levels of asymmetries are stronger for genes starting within CpG islands than in genes lacking this property. In contrast to all other species analyzed, we found a mutational pressure in dog and stickleback, promoting an increase of GC-contents in the proximity to transcriptional start sites.</p> <p>Conclusions</p> <p>We propose that the asymmetric patterns in transcribed regions are results of transcription associated mutagenic processes and transcription coupled repair, which both seem to evolve in a taxon related manner. We also discuss alternative mechanisms that can generate strand biases and involves error prone DNA polymerases and reverse transcription. A localized increase of the GC content near the transcription start site is a signature of biased gene conversion (BGC) that occurs during recombination and heteroduplex formation. Since dog and stickleback are known to be subject to rapid adaptations due to population bottlenecks and breeding, we further hypothesize that an increase in recombination rates near gene starts has been part of an adaptive process.</p
Elastic effects of vacancies in strontium titanate: Short- and long-range strain fields, elastic dipole tensors, and chemical strain
We present a study of the local strain effects associated with vacancy
defects in strontium titanate and report the first calculations of elastic
dipole tensors and chemical strains for point defects in perovskites. The
combination of local and long-range results will enable determination of x-ray
scattering signatures that can be compared with experiments. We find that the
oxygen vacancy possesses a special property -- a highly anisotropic elastic
dipole tensor which almost vanishes upon averaging over all possible defect
orientations. Moreover, through direct comparison with experimental
measurements of chemical strain, we place constraints on the possible defects
present in oxygen-poor strontium titanate and introduce a conjecture regarding
the nature of the predominant defect in strontium-poor stoichiometries in
samples grown via pulsed laser deposition. Finally, during the review process,
we learned of recent experimental data, from strontium titanate films deposited
via molecular-beam epitaxy, that show good agreement with our calculated value
of the chemical strain associated with strontium vacancies.Comment: 14 pages, 11 figures, 4 table
Expanded access to investigational drugs in psychiatry:A systematic review
Some psychiatric patients have exhausted all approved treatment options. Numerous investigational drugs are currently being developed and tested in clinical trials. However, not all patients can participate in clinical trials. Expanded access programs may provide an opportunity for patients who cannot participate in clinical trials to use investigational drugs as a therapeutic option outside of clinical trials. It is unknown to what extent expanded access occurs in psychiatry. We conducted a systematic literature search on PubMed, Embase, and PscyInfo, with additional information from ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform and FDA/EMA approvals, in order to find all expanded access programs ever conducted, globally, in the field of psychiatry. This resulted in a total of fourteen expanded access programs ever conducted in psychiatry. Given the prevalence of psychiatric disorders, the activity in clinical research in psychiatry, the regulatory framework enabling expanded access, and the impact of psychiatric disorders on patients, their families, and society, we had expected a higher utilization of expanded access. We propose that the psychiatric community, with pharmaceutical industry, should consider establishing and optimizing expanded access programs.</p
Performance Bounds for Grouped Incoherent Measurements in Compressive Sensing
Compressive sensing (CS) allows for acquisition of sparse signals at sampling
rates significantly lower than the Nyquist rate required for bandlimited
signals. Recovery guarantees for CS are generally derived based on the
assumption that measurement projections are selected independently at random.
However, for many practical signal acquisition applications, including medical
imaging and remote sensing, this assumption is violated as the projections must
be taken in groups. In this paper, we consider such applications and derive
requirements on the number of measurements needed for successful recovery of
signals when groups of dependent projections are taken at random. We find a
penalty factor on the number of required measurements with respect to the
standard CS scheme that employs conventional independent measurement selection
and evaluate the accuracy of the predicted penalty through simulations.Comment: Revised for publication. 21 pages, 10 figure
Modelling the influence of peers’ attitudes on choice behaviour: theory and empirical application on electric vehicle preferences
While the importance of social influence on transport-related choices is commonly acknowledged within the transport and travel behaviour research community, there remain several challenges in modelling influence in practice. This paper proposes a new analytical approach to measure the effects of attitudes of peers on the decision making process of the individual. Indeed, while most of the previous literature focused its attention on capturing conformity to a certain real or hypothetical choice, we investigate the subtle effect of attitudes that underlies this choice. Specifically, the suggested measure enables us to model the correlated effect that might indirectly affect the individual’s choice within a social group. It combines detailed information on the attitudes in the individual’s social network and the social proximity of the individuals in the social network. To understand its behavioural implications on the individual’s choice, the individual’s peer attitude variable is tested in different components of a hybrid choice model. Our results show that the inclusion of this variable indirectly affects the decision making process of the individual as the peers’ attitudes are significantly related to the latent attitude of the individual. On the other hand, it does not seem to directly affect the utility of an alternative as a source of systematic heterogeneity nor does it work as a manifestation of the latent variable, i.e. as an indicator
Compositional Design and Verification of a Multi-Agent System for One-to-Many Negotiation
A compositional verification method for multi-agent systems is presented and applied to a multi-agent system for one-to-many negotiation in the domain of load balancing of electricity use. Advantages of the method are that the complexity of the verification process is managed by compositionality, and that parts of the proofs can be reused in relation to reuse of components
The use of hyperspectral imaging for cake moisture prediction
In this paper, hyperspectral imaging is demonstrated to be a valid method for predicting the moisture content of baked sponge cakes. The application of this technology in the cake production environment, empowered by sophisticated signal & image processing techniques and prediction algorithms has the potential to provide on-line, real-time, non-destructive cake moisture monitoring
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